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From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Patent specification for improvements to a control mechanism with reference to gear boxes.

Identifier  ExFiles\Box 136\4\  scan0151
Date  21th March 1931
  
PATENT SPECIFICATION
Application Date: March 21, 1931. No. 8772/31. 372,040
Complete Left: Jan. 18, 1932.
Complete Accepted: May 5, 1932.
PROVISIONAL SPECIFICATION.
Improvements relating to Control Mechanism particularly with Reference to Gear Boxes.
I, BERNARD THOMSON, of Combe Close, Woldingham, in the County of Surrey, a subject of the King of Great Britain, do hereby declare the nature of this invention to be as follows:—
5 My invention relates to control mechanism, and is especially applicable to gear boxes.
10 My invention has for its object to provide an improved arrangement of control mechanism in which accidental displacement of the mechanism from the position in which it has been set by the operating lever or member, is effectively prevented.
15 My invention consists in a control mechanism in which the operation of a control lever or member in effecting movement of the mechanism into one or more operative positions, automatically locks the mechanism in position and/or operation of the control lever or member in effecting a movement of the mechanism from an operative position, automatically unlocks the mechanism.
25 My invention further consists in the improved control mechanism for gear boxes, to be hereinafter described.
In carrying my invention into effect, according to one form, and as applied by way of example to a three speed gear box in which the gear changes for the different speeds is effected by a ball-mounted gear lever, I arrange the two shifting forks for setting the mechanism in the various speed position, to slide on rods which are fixed in the casing of the gear box.
40 The bosses of the shifting forks forming the bearings for the forks on the guide rods, are each formed with an upwardly extending opening of rectangular section, and in each opening, a locking member is disposed. Each locking member is pivotally mounted on a pin which extends transversely between two opposite walls of the opening in which the locking member is situated so that the locking member may swing on an axis arranged at right angles to the axis of the corresponding guide rod.
50 The upper portion of each locking member projects beyond the opening in which [Price 1/-]
55 the locking member is disposed, and is formed with a recess of approximately semi-circular form with which the similarly formed lower end of the gear lever is adapted to engage.
60 The lower face of each locking member is provided with two teeth, one of the teeth being arranged at the forward end of the locking member and the other at the rear end thereof, while a hemi-spherical recess is formed on the lower face of the locking member centrally between the teeth. From the hemi-spherical recess, the lower faces of each locking member slopes slightly upwards to the inner faces of the teeth. The end of the locking members are rounded forming parts of circles struck with the axes of the pivot pins of these members as centres.
75 On each guide rod, two notches are formed corresponding to the forward and rearward positions of the corresponding shifting fork, while in the central position of the forks, the hemi-spherical recesses on the locking members are adapted to be engaged by balls resiliently mounted in holes in the guide rods.
85 In the central position of the striking forks, corresponding to the neutral position of the gear lever, the semi-circular recesses in the upper portions of the locking members are in alignment with one another, the locking members being held in this position by the teeth thereon which bear on the upper surfaces of the guide rods and by the spring-mounted balls which engage with the recesses on the lower faces of the locking members.
95 On moving the gear lever from the neutral position to effect a gear change, the upper end of the lever is swung, for example, laterally in a clockwise direction and rearwardly to effect the change. This movement causes the appropriate locking member to be selected and together with its co-acting shifting fork to be moved forwards on its guide rod, the spring ball being automatically released by the pressure applied to the lever to effect the movement. When the shifting fork has reached the position corresponding to the completed gear change,
372,040 COMPLETE SPECIFICATION 1 SHEET
Fig 1. Fig 3. Fig 2. Fig 4. Fig 5. Fig 6.
[This Drawing is a reproduction of the Original on a reduced scale]
Charles & Read Ltd. Photo Litho.
  
  


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